The invention relates to a scraper device for a milling drum mounted in a construction machine.
Such a scraper device is known, for instance, from DE 102 47 579.
The scraper device for milling drums of a construction machine described therein, in particular of a road milling machine wherein milling drums of different milling widths can be used within a maximum milling width, consists of a scraper blade that can glide on the surface milled or to be milled by the milling drum.
The scraper blade is required to scrape milled material, which accumulates behind the milling drum when seen in the direction of travel, from the milled surface in order to leave behind a thoroughly clean milled area. When doing so, the material that has accumulated behind the milling drum is fed to the milling drum once again until it is accepted and transported away by a transport device.
Previously known centering devices which consist, for example, of cams projecting laterally from the scraper blade, which engage with lateral guides of the scraper blade and restrict the lateral play of the scraper blade in the engagement position of these cams, have not been capable of preventing jamming. In the working position of the milling drum at maximum milling depth, the cams are not engaged with the lateral guides, thus permitting an increased lateral play of the scraper blade. This increased lateral play is required in the operating mode of the milling machine so as to enable unobstructed driving through bends during the milling operation. The milling drum can be set to different milling depths. When doing so, the scraper blade always has the same working position, in which the lower edge of the scraper blade is at the same height as the lowest portion of the cutting circle of the milling drum.
However, if the milling operation has to be interrupted due to, for instance, the replacement of tools, and the milling machine with the milling drum must dive into an existing cut, then it is very difficult for the machine operator to also lower the scraper blade into the previously milled track if the permitted lateral play is too large. If the scraper blade does not enter the existing milled cut due to the lateral play but hits the still untreated road surface with one side instead, then the scraper blade jams, and a high amount of effort is required to disengage a scraper blade that is jammed in this way. Frequently, several attempts are necessary to lower the scraper blade in the correct position, or the machine operator commences the milling operation without the scraper blade entering the milled track. Milled material then remains in the milled track, in which case there is the additional hazard of persons being injured by milled material that is thrown out through the unclosed opening of the drum housing.
Hence, the purpose of the invention is to further develop a scraper device of the type first above mentioned in such a manner that jamming of the scraper blade is prevented.